Nebraska head coach Bo Pelini looks for it after every substitution he makes.

Offensive coordinator Shawn Watson looks for it after every play he sends down from the coaches box. Running backs coach Tim Beck tries to find it in every practice.

With three more-than-capable running backs at the NU coaching staff's disposal this season, everyone is looking for the answer to one thing leading up to and during every game: who will emerge as "the guy.'

It's a loosely-worded title in the sense that there is no clear cut definition of what makes a running back "the guy" for a game. It can be who sees the holes the best, who's breaking tackles for extra yards, or even simply who's making the most plays.

This season, the Huskers find themselves with difficult luxury on a weekly basis, as senior running back Marlon Lucky and sophomores Roy Helu and Quentin Castille could all be starters on the majority of teams in college football. The problem for Nebraska's coaches is finding out how to split a limited number of carries between the three while also trying to find "the guy."

"We've got three good players," Pelini said. "We've got three really good football players and they all deserve snaps. That's a tremendous advantage because you keep guys fresh. I don't see any disadvantages. If a guy's hot, we're going to keep him going. We're going to give them all touches."

But when do the coaches know exactly when a guy is "hot"? How many quality runs does it take for a back to emerge as that game's go-to option, and are there enough carries in a game to give all three an opportunity to make their cases?

While the Huskers have yet to put together a game on the ground worthy of their lofty preseason expectations, two different backs emerged as the guy in NU's first two games this season. In the season opener against Western Michigan, Lucky earned the title with a team-high 12 carries for 43 yards and a touchdown. He also had two catches for 35 yards and another score.

However, Helu actually led the team in rushing in the game with 52 yards on seven carries. Helu again led the Huskers in rushing last week against San Jose State, finishing with nine carries for 59 yards. In comparison, Lucky had just 23 yards on seven carries.

Two-back systems are nothing out of the ordinary in today's style of football, but Castille serves as the third head in NU's three-headed rushing attack. Though his yards don't come close to Lucky or Helu (12 carries for 12 yards on the year), Castille gives the Huskers' hard-earned yards up the middle that help counter the other two's more agile running style.

Beck said the process of determining who the No. 1 guy is each game has more to do with a gut feeling of the coaches and basic observation of how each is running with the ball. He did note, though, that playing time has little to do with who makes the fewest mistakes.

"I don't take guys out if they make a mistake," Beck said. "I'm giving them opportunities early and seeing who's doing what I'm asking them to do, who's playing hard, who's executing their assignments, who's reading the blocks well Each one of those guys possess certain qualities that are better than others, and we try to feature them in that.

"Whatever the game needs you can kind of go with that guy at that point. But it could be completely different on Saturday and you could be talking about somebody else."

The decision may be difficult for the coaches, but it's sometimes even harder on the players. All offseason, all of Nebraska's running backs stressed repeatedly that none of them minded sharing the load in the backfield this year.

While that still may be the case, Lucky admitted that it can be difficult getting a good enough feel for the game to start running at his best. As a result, he said the running backs often feel pressure to score on every carry they get. Which, depending on how you look at it, could be both a good and bad thing.

"It's always hard with three backs for one person in the rotation to get into a rhythm, but we just gotta step it up," Lucky said. "Every touch we get, we gotta try to score. That's how it is. When you get hot, you get hot. You stay in. You're not going to take anybody out if he hot."